The present invention relates to a rotary encoder that generates a signal detecting the amount of change, i.e. rotational angle in rotation and rotating direction during rotational operation, and multi-operational electronic component, such as a mouse for a PC and a cellular phone, using the rotary encoder.
FIG. 14 shows a plan view of the contact portion of a conventional rotational type encoder (hereinafter referred to simply as RTE), which generates an electric signal detecting the amount of change (rotational angle) in rotation and rotating direction during rotational operation. rotational contact plate 1 rotatably mounted on base 5, and three flexible sliding bars 6, 7, 8 extended from base 5.
Rotational contact plate 1 has rotary contact 2 formed typically by insertion molding on the surface of an insulation resin-made circular board. Rotary contact 2 includes common annular contact 3 and teeth-shaped contact 4 for signal generating, with each tooth angled uniformly and extended radially from annular contact 3.
Flexible sliding bars 6, 7, and 8 have elastic contacts 6A, 7A, and 8A on each tip of the bars, respectively.
As shown in FIG. 14, elastic contacts 6A, 7A, and 8A are arranged parallel in a radial direction of rotary contact 2, and contact with rotary contact 2. Elastic contacts 6A contacts with annular contact 3, while elastic contacts 7A, 8A contact with teeth-shaped contact 4. On rotational contact plate 1, the contact spot of elastic contact 7A is displaced from that of contact 8A by xe2x80x9cDxe2x80x9d (indicated in FIG. 14) in a rotating direction of contact plate 1.
Following the rotating operation of plate 1, contact 6A slides resiliently on annular contact 3, and contacts 7A and 8A slide resiliently on teeth-shaped contact 4. As contact plate 1 rotates, electric signals having a rectangular wave, as shown in FIG. 15, are generated between contacts 6B and 7B, 6B and 8B. In FIG. 15, the rotational angle of plate 1 is described on the horizontal axis. Suppose that an electric signal generated between contacts 6B and 7B is designated as signal xe2x80x9cMxe2x80x9d, while an electric signal generated between contacts 6B and 8B is designated as signal xe2x80x9cNxe2x80x9d. In the prior art, the rotational angle and the rotating direction have been detected according to the number of signals xe2x80x9cMxe2x80x9d and xe2x80x9cNxe2x80x9d, and the phase difference (i.e., the angle difference) xe2x80x9cTxe2x80x9d between the two signals.
FIG. 16 shows a general perspective view of a rotary encoder with a push switch (hereinafter referred to simply as REPS), which functions as a multioperational type electronic component employing the RTE described above. FIG. 17 is a cross-sectional side view of the REPS shown in FIG. 16. As shown in FIGS. 16 and 17, RTE 12 is disposed on one side of mounting substrate 11 serving as a base, on the other side of substrate 11, self-restoring type push switch (hereinafter referred to simply as PS) 13 is disposed. RTE 12 is held on substrate 11 in a manner that it is movable in a vertical direction (indicated by arrows xe2x80x9cVxe2x80x9d in FIGS. 16 and 17.) On the other hand, PS 13 is fixed to substrate 11 so as not to move. FIG. 18 shows a general perspective view of mounting substrate 11.
As shown in FIG. 18, resin-made substrate 11 is provided with:
recess 15 having guide rails 14 for RTE 12 to move along;
recess 16 for fixing PS 13; and
three contact plates 18 (18A, 18B, 18C) having their respective three terminals 17 (17A, 17B, 17C) for leading electric signals of RTE 12 to the outside.
As shown in FIG. 17, RTE 12 is held by recess 15 in substrate 11 and guide rails 14 in a manner that it is movable in a vertical direction indicated by the arrow xe2x80x9cVxe2x80x9d.
As described above, RTE 12 comprises:
rotary contact 20A including an annular contact portion, and a teeth-shaped contact portion arranged outside of the annular contact portion, which is mounted on an inner surface of cylindrical operating knob 19; and
three flexible sliding bars 22A, 22B, and 22C extended in parallel from resin-made substrate 21.
Operating knob 19 is retained with substrate 11 in a manner that it is rotatable on cylindrical shaft 23. Each elastic contact of three sliding bars 22A, 22B, 22C connects resiliently with rotary contact 20A, having a parallel arrangement in a radial direction of rotary contact 20A.
Furthermore, three elastic contact legs 24 having electrical continuity with their respective elastic contact bars 22A, 22B, 22C, which protrude in an opposite direction from substrate 21, connect resiliently with three contact plates 18 (18A, 18B, 18C).
On the other hand, as shown in FIG. 17, PS 13 is fitted in recess 16 in substrate 11 so as not to move. Actuating button 25 of PS 13 is in contact with pushing portion 23A of cylindrical shaft 23 and pushes it up. Switching terminal 26, which transmits the electric signal from PS 13 to the outside, projects downwardly from substrate 11.
FIG. 19 is a partially sectioned side view depicting an example in which the REPS is mounted in an end-use apparatus. As shown in FIG. 19, leg 11A disposed on the bottom of substrate 11, terminal 17 of RTE 12, and switching terminal 26 of PS 13 are inserted into mounting holes 28 and 29 in wiring board 27 of the apparatus, and soldered. In this way, the REPS is mounted in an apparatus. Periphery 19A of operating knob 19, serving as an operating portion, protrudes from upper enclosure 30 of the apparatus.
The REPS of the prior art constructed as above operates in a manner, which will be described hereinafter.
First, RTE 12 will be described.
An operator rotates cylindrical operating knob 19 by applying a force on periphery 19A of knob 19 in the tangential direction (indicated by the arrow xe2x80x9cHxe2x80x9d in FIG. 16). This rotary motion causes rotary plate 20 to rotate on cylindrical shaft 23. According to the rotation, each elastic contact of three flexible sliding bars 22A, 22B, 22C slides on contact 20A including annular contact portion and teeth-shaped contact portion secured to rotary plate 20, while maintaining resilient contacts therewith. As a result, RTE 12 generates an electric signal corresponding to the rotating direction of operating knob 19. This electric signal is transferred to contact plate 18 on mounting substrate 11 from three elastic contacts respectively corresponding to three sliding bars 22A, 22B, 22C. The electric signal is further transferred to a circuit on wiring board 27 of the apparatus through terminals 17 for external connections.
Now, the self-restoring PS will be described.
The operator applies a depressing force on periphery 19A of knob 19 in a direction toward the central axis of rotation (i.e., the direction of the arrow xe2x80x9cV1xe2x80x9d shown in FIG. 19) against the biasing force of actuating button 25 which pushes RTE 12 upward. The depressing force shifts entire RTE 12 in the direction of the arrow xe2x80x9cV1xe2x80x9d along guide rails 14 of substrate 11. This movement causes pushing portion 23A of cylindrical shaft 23 to depress actuating button 25. The depressed motion of actuating button 25 actuates PS 13 to thereby generate an electric signal. The electric signal is transmitted through switching terminal 26 to the circuit on wiring board 27 in the apparatus. When the depressing force applied on knob 19 is removed thereafter, RTE 12 is pushed back and returns to its original position by a resilient restoring force of PS 13. This is how the REPS of the prior art operates.
However, the RTE of the prior art, as shown in FIGS. 14 and 15, generates two electric signals xe2x80x9cMxe2x80x9d and xe2x80x9cNxe2x80x9d for detecting the amount of change (rotational angle) in rotation and rotating direction during rotational operation. For this detection, the prior art has employed the arrangement: three contacts 6A, 7A, 8A of three flexible sliding bars 6, 7, 8 are placed in a parallel direction of rotary contact 2, such that common elastic contact 6A of sliding bar 6 contacts resiliently with annular contact 3, while two signaling elastic contacts 7A and 8A respectively disposed on sliding bars 7 and 8 are in resilient contact with teeth-shaped contact 4 extended from annular contact 3. For this arrangement, the RTE of the prior art inconveniently needs a large diameter of the entire RTE. Consequently, in the REPS functioned as a multi-operational electric component employing the RTE of the prior art, cylindrical operating knob 19 to operate RTE 12 needs to be made even larger in size. Moreover, the top end of mounting substrate 11 must be kept from protruding beyond upper enclosure 30 when mounting the REPS on the apparatus. Furthermore, a wide space is needed between upper enclosure 30 and wiring board 27 due to the structure in which the bottom surface of substrate 11 mounted on wiring board 27 of the apparatus has to be kept lower than the bottom position where knob 19 reaches. Thus, in the prior art, there has been a problem that an enclosure of the apparatus equipped with the REPS becomes so bulky in height size.
The present invention is intended to eliminate the foregoing problems of the past by realizing an RTE having a small-sized diameter, which generates an electric signal to detect the amount of change in rotation and rotating direction during rotational operation. In addition, with the improved RTE, this invention aims at providing a multi-operational electronic component not only having a cylindrical operating knob with small-sized outer diameter, but also having an enclosure of an end-use apparatus with reduced height.
The rotary type encoder of the invention comprises:
a contact substrate on which three fan-shaped conductive layers having respective leading terminals are disposed such that they are placed on the positions having a same distance from the center of the substrate; and
a movable contact plate having three elastic contacts, which have an electrical continuity with each other and are spaced with the radial angle of 120xc2x0. The movable contact plate is disposed so as to be rotatable on the center of the contact substrate.
Disposed on the positions having a same distance from the center of the contact substrate, the three elastic contacts resiliently contact with the substrate.
As the movable contact plate rotates, any two out of three elastic contacts have consecutively electrical continuity with any two out of three fan-shaped conductive layers. The continuity signal is led out from each leading terminal.
The three conductive layers on the surface of the contact substrate, each of which has the radial angle of 60xc2x0, spaced apart to subtend an angle of 80xc2x0 at the center of the substrate.
With such a structure, three different electric signals are generated between leading terminals of the three conductive layers when the RTE rotates. According to the generated number of the three signals and the generating order, it is possible to detect the amount of change (i.e. rotational angle) in rotation and rotating direction during rotational operation. The three elastic contacts having resilient contacts with the contact substrate are disposed on the positions having a same distance from the center of the substrate. This arrangement allows the RTE to have a smaller diameter. With such downsized RTE, it is possible to provide a multi-operational electronic component not only having a cylindrical operating knob with small-sized outer diameter, but also having an enclosure of an end-use apparatus with reduced height size.